S.D. Butterworth

Highly-efficient green light generation by quasi-phase-matched frequency doubling of picosecond pulses from an amplified mode-locked Nd:YLF laser

We report on first-order quasi-phase-matched frequency doubling of picosecond pulses to the green, using a sample of periodically poled lithium niobate. In cw mode-locked operation, 330 mW of average green power was generated with an average conversion efficiency of ~52%. With a quasi-cw mode-locked pulse train an average conversion efficiency of ~65% was achieved, and 1.3 W of green power (average power within the 10-micros pulse envelope) was produced. At these powers there was no significant photorefractive damage, as confirmed by measured M(2) beam-quality factors of ~1.1 for both output fundamental and second-harmonic beams.

Optical parametric oscillation in periodically-poled lithium niobate based on continuous-wave synchronous-pumping at 1.047µm

A singly resonant optical parametric oscillator is reported that uses a periodically poled LiNbO(3) crystal and is synchronously pumped by a cw mode-locked 1.047-microm Nd:YLF laser. Picosecond pulses were tunable from 1.67 to 2.806 microm. Mean output powers of 120 mW (90 mW) were obtained for the signal (idler) wave with an overall slope efficiency of 61% at a pump depletion of 75% when the oscillator was operating at three times above threshold.

Picosecond Ti:sapphire-pumped optical parametric oscillator based on periodically-poled LiNbO3

Periodically poled lithium niobate has been used in a singly resonant optical parametric oscillator pumped by a cw mode-locked Ti:sapphire laser. A tuning range of 1.15 to 2.4 microm was achieved when the pump was tuned, and this range was limited only by the mirror reflection bandwidth. Thresholds as low as 18 mW and an overall slope efficiency of 44% were observed, with average output powers of 130 mW (70 mW) for the signal (idler).

Generation of femtosecond pulses from order-of-magnitude pulse compression in a synchronously pumped optical parametric oscillator based on periodically poled lithium niobate

We demonstrate the generation of compressed, transform-limited 250-fs pulses, tunable in the near infrared, by means of synchronously pumped optical parametric oscillation in periodically poled lithium niobate. The almost 20-fold compression from the 4-ps pulse duration of the cw mode-locked Nd:YLF pump results in signal peak powers well in excess of the pump power.

Efficient, low-threshold synchronously-pumped parametric oscillation in periodically-poled lithium niobate over the 1.3 μm to 5.3 μm range

Abstract Using periodically-poled lithium niobate (PPLN), synchronously pumped by a Nd:YLF laser at 1047 nm, optical parametric oscillation is achieved with a mean threshold power as low as 7.5 mW, nearly an order of magnitude lower than previously reported. Output slope efficiencies (signal plus idler), at a signal wavelength of ∼1.7 μm (idler 2.7 μm), of up to 160% are observed. Efficient operation has been observed out to 5.3 μm, well into the infrared absorption edge of lithium niobate.

Low‐threshold picosecond optical parametric oscillation in quasi‐phase‐matched lithium niobate

We report a singly resonant optical parametric oscillator in periodically poled lithium niobate. synchronously pumped by the second harmonic of an amplified 10 µs pulse train from a continuous wave mode-locked Nd:YLF laser. Pulses of ~2 ps duration have been generated over the tuning range from 883 to 1285 nm with a typical threshold of 200 mW average power within the 10 µs envelope. The M 2 beam quality factor for the generated signal was ~1.1, indicating absence of any significant photorefractive damage.

Widely tunable synchronously pumped optical parametric oscillator

We describe a continuous-wave synchronously pumped singly resonant lithium triborate optical parametric oscillator that is tuned over the range 0.8–1.5 μm. At four times threshold, the pump depletion is 75%, and the oscillator converts 27% of the pump radiation into tunable output in picosecond pulses with 78-mW average power.

High-power widely-tunable picosecond pulses from an all-solid-state synchronously-pumped optical parametric oscillator

The operation is reported of an all-solid-state singly-resonant synchronously-pumped lithium triborate optical parametric oscillator (OPO). Two different configurations of the gain medium are reported. The first gain medium has antireflection-coated faces, and the second Brewster-angled faces. The antireflection-coated (Brewster-angled) device had an oscillation-threshold average pump power of 90 mW (170 mW) at 523 nm. At 2.8 (1.9) times threshold, the pump depletion was 50% (60%), and the oscillator converted 30% (34%) of the pump radiation into tunable output in pulses of ~1 ps duration. Temperature-tuned noncritical phase matching in the parametric oscillator yielded radiation continuously tunable over the range 0.85-1.36µm (0.72-1.91µm) with up to 43 mW (89 mW) of average power in the resonated wave output, and 33 mW (44 mW) in the nonresonated wave output.

Tunable efficient CW ultraviolet generation in periodically poled lithium niobate

Summary form only given. SHG for blue and green generation has been demonstrated in periodically poled LiNbO/sub 3/ (PPLN), and we recently obtained efficient SHG of a pulsed 800 nm laser. Here we report efficient CW UV generation close to the absorption edge in PPLN by intracavity SHG of a Ti:sapphire laser.

Efficient cw synchronously pumped optical parametric oscillation beyond 5 /spl mu/m in periodically poled lithium niobate

Periodically poled lithium niobate (PPLN) offers many attractive features for optical parametric oscillation (OPO). These include high nonlinearity and noncritical quasi-phase-matching in a wide spectral range, making it well-suited to synchronously pumped operation. Using a cw mode-locked 1047-nm pump, we recently demonstrated a low-threshold singly resonant oscillator tunable over the range 1.67-2.8 /spl mu/m. In this contribution we report a major extension of this tuning range, demonstrating singly resonant operation in the range 1.3-5.3 /spl mu/m, while still retaining low threshold and high efficiency. Additionally we have observed oscillations with idler wavelengths out to 6.3 /spl mu/m. This now offers a widely tunable source covering wavelengths well into the mid-IR. This is made possible by the use of PPLN, which allows operation at longer wavelengths than bulk lithium niobate. In addition, the high round trip gain in pulsed pumping of PPLN-based OPOs allows generation of coherent, tunable radiation even in spectral regions where the crystal is highly absorbing. Thus, pumping with a mode-locked 1047-nm Nd:YLF laser, we were able to generate 10 mW of idler average power at 5.3 /spl mu/m for 800 mW of incident pump power, with an oscillation threshold of under 300 mW. We also present results of the coupled-wave analysis of parametric oscillation in the presence of idler absorption.